Assuming you haven't tinkered with the pre-installed software/drivers in some way that could cause camera glitches, I can only see two real possibilities here:

1. You got a lemon camera and you just need to return the unit or get warranty service.

2. Forgive me, but is it possible that the unit shipped with some sort of protective tape or cap over the camera that just needs to be removed? I don't mean to sound insulting, but you might be amazed how many people are stymied by things like that.